The present invention relates to an optical apparatus having a driving source for driving a lens in an optical axis direction, and particularly, to an optical apparatus which includes a vibration or electromagnetic type linear actuator for use as a driving source.
Some optical apparatuses include an electromagnetic type linear actuator or a vibration type linear actuator for use as a driving source for driving a lens (for example, see Japanese Patent Laid-Open No. 8(1996)-179184, and Japanese Patent Laid-Open No. 10(1998)-90584).
In the optical apparatuses proposed in Japanese Patent Laid-Open No. 10(1998)-90584 having the vibration type linear actuator, the vibration type linear actuator is formed of a vibrator which produces vibration through an electromechanical energy conversion action and a contact member which is in press contact with the vibrator. The vibrator and the contact member are relatively moved in the optical axis direction to move a lens.
Japanese Patent Laid-Open No. 10(1998)-90584 discloses some lens driving methods using such a vibration type linear actuator. For example, a method is disclosed in which the vibrator is fixed to a lens holding member, the contact member is fixed to a stationary member of a lens barrel, and the vibrator is caused to produce a driving vibration, thereby moving the lens holding member together with the vibrator. Another method is also disclosed in which the contact member is fixed to a lens holding member, the vibrator is fixed to a stationary member of a lens barrel, and the vibrator is caused to produce a driving vibration, thereby moving the lens holding member together with the contact member.
The vibrator requires a wiring connection for receiving electrical signals that are applied on its electromechanical energy conversion element. In the case where the vibrator is moved together with the lens in the optical axis direction, the handling of the flexible wiring board is complicated, such as giving a curved shape to it, for allowing the movement of the vibrator. Further, the design freedom of the optical apparatus is limited because other members must be arranged away from a motion space of the flexible wiring board. This results in an increase in size of the optical apparatus. Therefore, the configuration is preferable in which the vibrator is fixed, and the contact member is moved together with the lens holding member.
However, a contact member having a long length in the optical axis direction is required for a lens having a large moving amount (movable range). Consequently, when the long contact member is moved together with the lens in the optical axis direction, a long space in the same direction is required to allow the movement in the optical apparatus.
It is possible in some degree to suppress the increase in size of the optical apparatus by devising the handling of the flexible wiring board that has flexibility. However, the contact member has no flexibility, so that the configuration in which the long contact member is moved together with the lens inevitably causes the increase in size of the optical apparatus.
These problems are the same in using an electromagnetic type linear actuator in which a coil and a magnet are relatively moved in the optical axis direction to drive a lens.